On Wed, Mar 30, 2016 at 10:58:38AM -0700, Mark Brown wrote: > When ACPI was originally merged for arm64 it had only been tested on > emulators and not on real physical platforms and no platforms were > relying on it. This meant that there were concerns that there might be > serious issues attempting to use it on practical systems so it had a > dependency on EXPERT added to warn people that it was in an early stage > of development with very little practical testing. Since then things > have moved on a bit. We have seen people testing on real hardware and > now have people starting to produce some platforms (the most prominent > being the 96boards Cello) which only have ACPI support and which build > and run to some useful extent with mainline. > > This is not to say that ACPI support or support for these systems is > completely done, there are still areas being worked on such as PCI, but > at this point it seems that we can be reasonably sure that ACPI will be > viable for use on ARM64 and that the already merged support works for > the cases it handles. For the AMD Seattle based platforms support > outside of PCI has been fairly complete in mainline a few releases now. > > This is also not to say that we don't have vendors working with ACPI who > are trying do things that we would not consider optimal but it does not > appear that the EXPERT dependency is having a substantial impact on > these vendors. > > Given all this it seems that at this point the EXPERT dependency mainly > creates inconvenience for users with systems that are doing the right > thing and gets in the way of including the ACPI code in the testing that > people are doing on mainline. Removing it should help our ongoing > testing cover those platforms with only ACPI support and help ensure > that when ACPI code is merged any problems it causes for other users are > more easily discovered. > > Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> I'm fine with dropping the EXPERT dependency (of course, not a cc stable). While arm64 ACPI is not "done" yet (nor is DT; there are important ongoing developments like PCIe, IORT), I think the core arm64 ACPI support passed the EXPERT stage. I also don't think a default y would imply any maintainer endorsement; vendors targeting ACPI are already doing this for various reasons (distro requirement, certain ACPI features like RAS). But, hopefully, it will encourage more vendors to start upstreaming their ACPI-related patches. However, building ACPI by default on arm64 doesn't mean that we can ignore potential misuses like PRP0001+_DSD blindly following DT (mis)concepts, breaking compatibility with older/newer firmware (this goes in both directions) or using ACPI for SoCs where it is clearly not suitable (e.g. non-SBSA). Such patches should be NAK'ed accordingly. > diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig > index 82b96ee8624c..bf5dc1ac3446 100644 > --- a/drivers/acpi/Kconfig > +++ b/drivers/acpi/Kconfig > @@ -5,7 +5,7 @@ > menuconfig ACPI > bool "ACPI (Advanced Configuration and Power Interface) Support" > depends on !IA64_HP_SIM > - depends on IA64 || X86 || (ARM64 && EXPERT) > + depends on IA64 || X86 || ARM64 > depends on PCI > select PNP > default y Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> That said, I'd like to see an opinion from the arm-soc maintainers since they were active on the original arm64 ACPI threads introducing this dependency (and I think they have the right to veto ;)). -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
